Conformationally restricted congeners of the opiate agonist 5-m-hydroxyphenyl-2-methylmorphan were prepared as probes to examined topological requirements for in vitro binding to opiate receptor subpopulations. Two congeners were inactive in vivo as agonists or antagonists and did not bind appreciably to opiate receptor preparations. One congener was a weak antagonist with no agonist properties and had a weak binding constant for opiate receptors. Work is presently progressing on the synthesis and biological evaluation of further members of this series.